Core retainer



March 22, 1932. C. A DEAN 1,850,386

CORE RETAINER Filed July 19, 1930 K Szlg 7 l is 3mm/tor @Aar/es cmqPatented Mar. 212, i932 i UNITED STATES CHARLES A. DEAN, OFIBAKERSFIELD, CALIFO'BNlA f CORE RETAINER Application. led Iuly 19,193i). Serial No. 489,124.

This invention relates to improvements in earth boring,` andparticularly to drills for obtaining sample cores. 4

Broadly, it is an object of this invention to provide meansfor obtainingand for retaining a core positively in a drill and to combine exibilitywith certainty of action in the core retaining means. This isaccomplished by an improved form and mounting of grip or dog to beprojected into the core in a controlled manner, and by otherimprovements herein Set forth.

Heretofore drills have been designed to cut cylindrical or otherportions through strata to be sampled, and to retain such portionswithin the drill. lFrequently in present day operations these samplesare taken many thousands of feet below the surface and under conditionsthat continually tend to destroy the accuracy, if not the existence, ofthe sample. of the drill, for example, usually are surrounded by viscousfluid, such as mud, that tends to counteract the action of such means asheretofore have been pro-vided to preserve a core while it is beingraised tothe surface. Further, a core frequently remains fastened orcemented to the bottom of the drill hole to such extent that either itis not extracted at all, or else is broken in being raised.- Thesefactors are illustrative of variouscauses of uncertainty that interferewith dependable sampling in earth drilling, as for example in oil welldrilling.

In core taking, various types of drill may be employed, such as a churndrill or a rotary drill. For the purpose of illustration, reference ishad to a rotary drill of the type frequently used in oil well drilling,but it will be apparent that suchreferences are illustrative rather thanlimiting, and that the principles of this invention may be extendedwithin the purport of the claims hereinafter presented.

Referring to the drawings z Fig. l'represents in general assembly avertical section of the rotary type of core drill, showing the form andarrangement of one form of core retaining means.

The sampling or cutting portions Fig. 2 is a section'ialong the line 2-2of Fig. 1.

Fig. 3 is a side elevation of a core retaining element and of thatportiongof the drill is illustrated as being separable. It carriessplines or feathers 7 engaging complementary positions of the outerbarrel, as shown in Fig. 2, both to guide the inner barrel to apre-designed position and to impart rotary motion to it. To the lowerend of this core barrel a pilot or core cutter Sis' secured in anydesired manner. This core cutter and container thus is rotatable withthe outer barrel but free to rise and fall relatively to it.

Through an appropriate lower portion of the inner core barrel there areprovided openings 9, suitably spaced and preferably upwardly directedinwardly. Through these are inserted pins or dog elements 10. Suitableyforms of these dogs are illustrated as having spherical heads, butcylindrical or other terminal portions may be provided, so that theseelements may project through the inner barrel and be free to pivot attheir ,bearing points. Through the outer barrel are provided openings 11preferably registering with these dogs, such that these dog-elements maybe inserted'or removed therethrough, and also preferably may pivottherein.y Appropriate screws or bushings 12-are then inserted tocomplete a housing or seatfor the dogs andV to retain them.

lt will be observed from this description and the accompanying drawingsthat in the example given the head of the core gripping dog is engagedby the housing or pocket of the outer drill barrel, and that thepiercing end of the dog is -elongate and relatively inflexible and is ofsubstantially uniform contour, and that as the dog pivots, it slides sothat its end pierces the core alongksubstantially a straight line. Thusthe dog is relatively strong and is adapted to pierce'a core and to bewithdrawnpositively therefrom with a minimum of injury to the core.

l The-usual space or fluid conduit 13 between the inner and outerbarrels communicates with the pivot portion or seat for the dogs so`that the pivot is kept free by the wash of fluid, this washing actionbeing facilitated by the circular contour of the head ofl the dog.Various forms of housing or bushing and of conduit connections willserve to accomplish this purpose.

In operation, the form of drill illustrated will be rotated with thepilot drill resting or pushed against Ithe' bottom of the drill hole.The core cylinder thus will be at an upper position relatively to theouter barrel.

, The dogs 10 will be pivoted, their outer ends pulled downwardly Abycoaction with the outer barrel and the inner ends withdrawn into theopenings of the inner barrel. Thus the core may be cut and fed into theinner barrel while the dogs by positive action are kept withdrawn.

When the whole drill israised the Weight of thecore and inner barrelbring that barrel to a lower position with respect to the outer barreland thus positively rotate the gripping ends ofthe dogs into the corebody. Should the pilot drill again be pressed against the bottom of thedrill hole, these dogs will be withdrawn and the drill may be rotatedwithout interference between the core and the dogs. l

In some instances the core becomes cemented or otherwise remainsfastened to the bottom of the drill hole. This invention permitscounteracting of this fault by appropriate action of the dogs. Anyslight or desired raising of the drill will tend to project the dogsinto the core and as the drill then is rotated these dogs will graduallyand controllably cut the core loose Afrom the bottom. They then willretain it as normally.

It will be observed that appropriate de- -sign of the splined sleevewill provide not only suitable guides for the dogs, but also willcommunicate rotary motion between the outer`and inner core barrels. Insome types of drill this latter action may not be necessary, as in achurn drill.

The assembly as illustrated in Fig. 1 is particularly desirable since itpermits ready removal of the inner barrel from the outerA barrel withoutremoving the individual dog elements. The core suitably may be extractedfrom the inner barrel in either direction. Other assembly will bepossible with various modifications of drill. Also positively actu ateddogs may be provided for existing drills. Nor is this inventionrestricted to the preferred form or mounting of dogs illustrated herein,but other kpositive actuation will be within `the scope of the appendedclaims except as limited by the prior art.

In accordance with the patent statutes illustrative embodiments of thisinventionhave been described, but the invention is not limited thereto,within the terms of the claims,

except as limited by the prior art. l,

of a drill barrel and with completely cylindrical outer walls extendingto its lower end, an inner tubular core container telescopically mountedwithin the collar, with interior splined connecting means intermediatethe wallsofuthe two to prevent relative rotation, and core dogs having acore-piercing end and having a head end mounted within the collar forengagement thereby to cause the head both to. rise and to fall, the corecontainer and the dogs being adapted for the core-piercing end to slidelengthwise into and from a core on corresponding relative verticalmovement between container and outer collar.

3. A core drill comprising a tubular collar with its upper portionattachable to the end of a drill barrel, and withcompletely cylindricalouter walls extending to its lower end, an inner tubular core containertelescopically mounted Within the collar, with interior splinedconnecting means intermediate the walls of the two to prevent relativerotation,V

head end pivotally mounted within the chambers and positively engageabletherein `by the collar for causing the head both to rise and tofa1l,the'core container and the dogs being adapted for the core-piercingend to slide lengthwise into and from a core on corresponding relativevertical movement between container and outer collar.

4. A core drill comprising a tubular collar with its upper portionattachable to the end ofl adrill barrel and with completely cylindricalouter walls extending to its lower end, an inner tubular core containertelescopically mounted within the collar, with interior splinedconnecting ymeans intermediate the walls ot the two to preventrelativerotation, chambers in the inner wall of the collar, core dogs having acore-piercing end and having an integral'arcuate head end pivotallymounted' within the chambers and positively engageable by the collar forcausing the head both to rise and to fall, the walls of the corecontainer having openings extendin upwardly from the collar and adaptedwitl dogs 'for the core-piercing end to 'slide into and from a core oncorresponding relative verprojecting over the face of the openings todivert liquid from entering, and/a fluid assage having an outlet belowthe core ogs and extending between core container and outer collar incommunication with the coredog heads to maintain freedom of pivotalaction.

5. A core drill, comprising a tubular collar with its upper portionattachable to the end of a drill barrel and with completely cylindricalouter walls extending to its lower end, reamer blades attached to thebottom of the collar, an inner tubular core container mountedtelescopically within the collar with intrior splined connecting meansintermediate the walls of the two, to prevent relative rotation,chambers in the inner wall of the collar, core dogs having a.5core-piercing end and having a head end pivotally mounted Within thechamber and positively engageable by the collar for causing the headboth to rise and to fall, the core-container having openings with a wallthereof extending upwardly from the collar and adapted with the dog forthe corepiercing end to slide into and from a core on correspondingrelative movement between container and outer collar, and core-cuttingblades below the reamer of less diameter than the reamer and detachablyterminating the core container. Y

6. A core drill, comprising a tubular-collar with its upper portionattachable to the end of a drill barrel and with completely cylindricalouter walls extending to its lower end, reamer blades attached to thebottom of the collar, an inner tubular core container mountedtelescopically within the collar with in-v terior connecting meansintermediate the walls of the two to prevent relative rotation, achamber in the inner Wall of the collar, core dogs having acore-piercing end and having a head end pivotally mounted within thechamber and positively engageable by the collar for causing the headboth to rise and to fall, the core-container having openings with awallthereof extending upwardly from the collar and adapted with the dogs forthe core-piercing end to slide into and from a core on correspondingrelative movement between container and outer collar, arluid passagehaving an outlet below the core dog and extending between core containerand outer collar in communication with the core-dog heads to maintainfreedom of pivotal action,`

and core-cutting blades detachably terminating the core container belowthe reamer.

In witness whereof I aix my signature.

CHARLES A. DEAN.

